从单位转换为int

Question

我在某个地方发现了这个代码，使图像正方形

public static Bitmap PadImage(Image originalImage)
{
     int largestDimension = Math.Max(originalImage.Height, originalImage.Width);
     Size squareSize = new Size(largestDimension, largestDimension);
     Bitmap squareImage = new Bitmap(squareSize.Width, squareSize.Height);
     using (Graphics graphics = Graphics.FromImage(squareImage))
     {
         graphics.FillRectangle(Brushes.White, 0, 0, squareSize.Width, squareSize.Height);
         graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
         graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
         graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

         graphics.DrawImage(originalImage, (squareSize.Width / 2) - (originalImage.Width / 2), (squareSize.Height / 2) - (originalImage.Height / 2), originalImage.Width, originalImage.Height);
     }
     return squareImage;
}

但我在第一行收到错误

int largestDimension = Math.Max(originalImage.Height, originalImage.Width);

我得到的错误是

  

无法转换为System.Web.UI.WebControls.Unit＆＃39;到了＆＃39; sbyte＆＃39;

我尝试使用Convert.ToByte，但无法正常工作。

我如何摆脱这个错误？